After a quik look over your list I thought it was a pretty solid list. But I think there are some things you might concider.

I personally dont see the use of the dread knight power on your vampire. It is allrdy at WS7 and this power forces him to challenge, resulting in him fighting alot of unit champions and thus wasting his attacks. I would switch this power for quikblood, it gives him always strike first and on I7 he may re-roll failed to hit rolls almost all of the time!

Further I would definitely drop a necromancer and upgrade your vamp to level 2, this frees up some points for the stuff I will mention in a second. Your core looks fine to me, its all about playstyle.

I am worried about your hard hitting troops as it seems you only have 1 (the vargheists) I really suggest throwing in a unit of at least 24 grave guard. They are a very reliable unit at S4 T4 4+AS 6+ parry save and killing blow. Further I really advice a unit of 5 hexwraiths. They are ethereal so they are hard to target. They have vanguard which lets them move before the game. They can move through terrain and units alike unhindered. This makes them exelent war machine/non-magical monster and character hunters.

In your rare choice I would really put a terrorgheist in there. The scream on the gheist is one of the most powerfull ability's in warhammer and I suggest you take advantage of it.

This is just some advice and what you do with it is entirely up to you! hope it helped!

Thank you Enarion for your reply,
You have a good point, concerning dreadnkight, I might just switch to ASF. As for the necromancers, they are of crucial importance: my adversaries REALLY despise invocation of nehek, to the point that I had some issues casting it (dispel frenzied players, dispel scrolls addicts...) so, by having 3 potencial nehek per phase + a cursed book that is going to help me either way (they try to dispel it, or the hex works aiding my frail troops.) the necromancers are therefore really handy, considering the pathetic figthing ability of skeletons and zombies. As combat resolution goes...undead always lose. Nehek is CRUCIAL...that's wy I'm putting 2 in the same unit, with the mortis engine babystting it.
I thought about the hexwraiths...but they are kinda expensive and they are kinda slow...AND combat resolution wise, they are going to lose, since my adversaries usually play with tons TONS of core, horde troops and very little anything else (I hate skaven)
Varghulf and Vargheist are both pretty fast moving and hard-hitting. I really like garve guards...but they lack manoeuvrability. My list would be too slow and static.
Anyhow, am I making sense?

Just a thought here, but i think you could benefit from splitting your unit of zombies into 2! this way when you cast invo and hit them both you will gain 4D6(2D6 per unit) giving you two solid sized units.

Note that the hexwraiths are ethereal and cant be damaged by anything that isnt magical. if you charge a block of 50 clanrats with 5 hexwraiths, you will always win combat unless they gain magical attacks somehow.

enarion,
It really depends if the hexwraiths do manage to kill 5 of them perhaps...but, banner, ranks etc...the scaven just might win. I've been playing a few games and I have to say that combat resolution is the undead's worst nigthmare. I think that the role of the hexwraiths is a support role. charging head-on a 50 clanrats unit doesn't seem all that promising (or maybe I'm just scared of combat resolution), they have no banner, so you really have to rely on their attacks, with ws3 won't always hit home...on the other hand, if he has 3 ranks, one banner, a battle standard...your chances of winning will greatly deplete, and if you have no luck, you will end up losing models from combat resolution...

Oh! and I remembered why I haven't put ASF on my vamp lord; he has the nigthshroud, wich makes enemies have ASL, AND cancels strength bonuses weapons.

I like the idea of having 2 squads of 25 zombies, nice one!! with a decent magic phase they can really get bolstered fast...

enarion,
It really depends if the hexwraiths do manage to kill 5 of them perhaps...but, banner, ranks etc...the scaven just might win. I've been playing a few games and I have to say that combat resolution is the undead's worst nigthmare. I think that the role of the hexwraiths is a support role. charging head-on a 50 clanrats unit doesn't seem all that promising (or maybe I'm just scared of combat resolution), they have no banner, so you really have to rely on their attacks, with ws3 won't always hit home...on the other hand, if he has 3 ranks, one banner, a battle standard...your chances of winning will greatly deplete, and if you have no luck, you will end up losing models from combat resolution...

Oh! and I remembered why I haven't put ASF on my vamp lord; he has the nigthshroud, wich makes enemies have ASL, AND cancels strength bonuses weapons.

I like the idea of having 2 squads of 25 zombies, nice one!! with a decent magic phase they can really get bolstered fast...

I agree, sending out lone characters and single file units against hordes is a bad idea... 3 ranks + banner = 4 combat rez right off the bat (assumes no wounds or flank charges or bsb, or warbanner, etc.) Hexwraiths are just not going to do that much damage. The entire unit will crumble in 2 (maybe 3) rounds of combat. Hexwraiths are much more effective autohitting by running through units. Great to hold off knights of any kind from getting flank charges or bum rushing warmachines.

Even if you throw a super tooled up lord at a horde he'll probably lose, run and get rundown.

I prefer black knights (models are cooler anyway) with an unbreakable spirit and 2+ sv AND a str 6 charge they really deliver. On top of that you can put your vampire general with the squad and get march, as well as an extra powerful figther.

I think I'd do that... and give the vampire summon creatures of the night and put a dire wolves squad in front of my black knights. That way you can screen your expensive cavalry AND invoque dire wolves beyond their starting unit size. Wolves are cheap, fast, and act as four-legged-sacraficial-zombies.

Now I have to disagree with you about black knights. I would much rather take grave guard with great weapons. They will always have strength 6(not just on the charge) sure they dont have as good a save but they rez easier because they are infantry and you can get more rank bonuses in combat.